This invention relates to improvements in the actuator of a rotating frame animal trap. By a rotating frame animal trap is meant a trap which comprises a pair of similar frames which may be of a generally square or rectangular shape or of part-trapezoidal shape, and are made of round wire stock, pivotally connected at adjacent ends for relative rotation on a common axis so as to form by their sides two pairs of co-acting jaws. At least one actuator made of round wire stock, consisting of arms springbiased at one end so that the other ends, if unobstructed, would move away from each other to a distance substantially greater than the length of the frame ends, and having each arm terminating in a generally circular ring, adapted to encircle one set of adjacent ends of the frames, is used to urge the jaws towards, and maintain them in closed position. Such a trap is described in my U.S. Pat. No. 3,010,245, dated Nov. 28, 1961 (square or rectangular shape), or my U.S. Pat. No. 3,760,531, dated Sept. 25, 1973 (part trapeziodal shape). The ends of these rotating frame traps which cooperate with the rings are shaped so that, when the trap is in open, set position, outer portions of each end lie substantially parallel to each other, while the central portions of these ends form a cross with each other between the actuator rings. A suitable release mechanism (for example as described in my U.S. Pat. No. 3,010,245; Lehn, U.S. Pat. No. 2,947,107, dated Aug. 2, 1960; or my U.S. Pat. No. 3,762,094, dated Oct. 2, 1973) maintains the frames in open position when the trap is set, but when the trap is sprung, releases the frames so as to permit, as the result of the action of the actuator rings on the frame end, rapid rotation of the frames through an angle of about 90.degree., so that the jaws quickly strike and squeeze an animal in the trap to kill it.
A significant drawback of such traps arises from the fact that the clamping force of the trap increases as the trap closes, and reaches a maximum as the actuator rings reach the ends of their runs and bear against the extremities of adjacent ends of the trap frames. When bulky-bodied animals are caught in the trap, their body size may prevent the jaws of the trap from closing enough so that the actuator rings can expand sufficiently about these adjacent ends and thus develop enough leverage and clamping force to quickly kill the animal. It can therefore be seen that the humane efficiency of the trap (i.e. the trap's ability to kill any desired animal passing through it, large or small, so that the animal, when caught by the trap, will be killed as quickly as possible) is adversely affected insofar as bulky animals are concerned.
One solution to this problem is to use actuator rings of greater diameter. When a bulky-bodied animal is caught in the trap, even though the jaws do not close completely, the actuator rings could still expand to fully expanded position about adjacent frame ends. However, the initial speed of closing of the trap is sacrificed when such larger rings are used. In addition because of the enlarged rings, there is increased likelihood that the rings in fully expanded position will not bear against adjacent frame ends to urge them closed and thereby exert sufficient clamping force on the jaws of the trap. This would be particularly true when a slim-bodied or small animal was caught in the trap. In such a case, the clamping force might well be insufficient to kill the animal or, in some cases, even to prevent the trapped animal from struggling free of the trap.
In my U.S. Pat. No. 3,760,531, I described a construction of trap frame requiring a downwardly pointing, wedge-shaped space between at least the upper portions of the jaws of the trap when they were in tightly closed position so that the jaws might have a Y appearance, when viewed from the side. This wedge-shaped space was designed to permit the use of such enlarged actuator rings which would expand to fully expanded position about their adjacent frame ends even when bulky animals were caught, and at the same time ensure that sufficient clamping force was generated by the rings in this position. Such bulky animals would normally be caught higher up in the trap so that the wedge-shaped space would engage some of the animal's bulk without preventing further closing of the jaws of the trap. The difficulty here is that when an animal with a bulky body and short legs, for instance, a beaver, is caught in such a trap, the wedge-shaped space may be located too high in the jaws of the trap to be effective. As well, if an animal having a long slender body, such as an otter, is caught in this wedge-shaped space in the upper portions of the trap, then the trap may not kill the animal, but may simply hold the animal until the animal dies in pain or from starvation.
It is an object of the present invention to provide an improved actuator for rotating frame animal traps, which will increase their humane efficiency. It is a further object of the invention to provide an economical improvement which can be made to a given rotating frame animal trap which will result in a greater variety of animals being killed instantly by the trap, or which will result in the death or unconsciousness of a greater variety of animals within a shorter period of time, thereby increasing the trap's versatility in that one size of trap can be used more effectively and humanely to trap animals of different sizes and shapes.